(1) Field
The disclosed methods and systems relate generally to determining a position of a probe, for example, positioning of pipettes in liquid handling and/or liquid level sensor systems.
(2) Description of Relevant Art
Probes can be used in many different types of systems, including for example, liquid level sensing systems, where a pipette can be used as a probe to aspirate and/or dispense a liquid from and/or to a container (e.g., a well in a multi-well plate). Recent advancements in such systems focus on the challenge of withdrawing and/or dispensing precise small volumes of a liquid using a pipette without contaminating the liquid. Several manual and automated liquid-measuring systems are available for this purpose.
In several of these systems, a pipette probe is movably mounted over a container (e.g., well in a multi-well plate), and vertically lowered into the container until the tip of the probe/pipette reaches a desired level below or above the upper surface of the liquid (the meniscus). An amount of liquid may then be withdrawn from or dispensed into the container.
A consideration in liquid level sensing is properly positioning the pipette as it is lowered into a container. Generally, in a liquid handling embodiment, a cantilevered arm that includes one or more pipette tips is moved over and/or substantially parallel to one or more wells of a multi-well plate before moving in a direction that is substantially orthogonal to the wells to allow for aspiration and/or dispensing as provided herein. In some embodiments, an individual pipette may have contact with one, more than one, and/or all of the wells in the plate. Because a cantilevered arm may present variation in one, two, or three directions and/or dimensions along the arm, and further because the coordinate system of the arm is generally not aligned with the coordinate system associated with the multi-well plate, difficulties can arise when aspirating and/or dispensing.